The invention relates to a single- or multi-pole compact circuit breaker of narrow construction for protecting equipment. Such circuit breaker constitutes an operating element of the equipment and is installed in a multiplicity of electrical apparatus and devices such as household applicances, office machines, control devices for manufacturing and assembling automats and the like. The circuit breaker acts as an on-off switch and protects the respective circuits and loads against short circuits and overloads, in addition to the simultaneous switch function. In most instances heretofore a separate fine-wire fuse or a melting fuse was provided for the protection separate from the on-off switch. Such fuse must be replaced after each defect and the replacement is costly and involved.
The present protection circuit breaker is comparable in its general construction and function to the known power line circuit breaker comprising a mechanical cocking drive for operating a breaker contact arrangement which may be switched on manually and which may be freely tripped either manually, electromagnetically, and electrothermally. The breaker contact arrangement is located in front of a spark quenching device. Such line protecting circuit breaker is, however, as a rule, continuously switched on and it is required that the circuit breaker can be switched on again after the removal of a fault following a short circuit or excess current tripping.
Contrary thereto, the equipment protecting electrical circuit breaker constitutes in its function a switch element which is frequently operated manually. Such switch element is additionally constructed to assume the above mentioned protection or monitoring functions so that the need for a separate safety fuse within the user current circuit may be obviated. Additionally, it is desirable to provide the equipment switch, or rather, the equipment protecting circuit breaker with a further contact arrangement as an auxiliary feature. Such a feature is supposed to provide an information of the respective switch or breaker condition in accordance with its switched on or switched off position within a separate signal or control current circuit. Thus, the auxiliary feature shall be able to indicate in a suitable manner the operational condition of the electrical appliance. The indication may, for example, be optical or acoustical. In the alternative or additionally the auxiliary feature may control other auxiliary units in accordance with the switch position or the switch condition of the circuit breaker.
In connection with the known power line circuit breakers or excess current protectors of the above mentioned type which are substantially larger, it is known to provide these excess current or line circuit breakers with an auxiliary switch as disclosed in German Patent Publication (DE-OS No. 3,038,511). In this connection such auxiliary feature, however, does not pose any special difficulties because the spacial arrangement of the switching and tripping mechanism in the upper portion of the conventional circuit breakers makes it generally possible to also install in this zone an auxiliary contact arrangement without any substantial modification. The contact arrangement is operated synchronously with the movable main contact of the breaker. The auxiliary contact arrangement has a smaller load rating and respectively it requires little space so that its installation is relatively easy.
On the other hand, substantial difficulties are encountered in connection with the equipment protecting circuit breaker disclosed herein if the additional accommodating of switching means, tripping members, and a quenching device is required in the space available inside the circuit breaker if its outer dimensions are not to deviate, or to deviate only insignificantly, from the installation dimensions of prior art on-off switches without such protective features. This fact explains why heretofore the constructor did not even consider providing an equipment protecting circuit breaker with a further contact arrangement.